The invention relates to a motor-vehicle door latch with a latching mechanism formed as a standard pivotal bolt and a latching pawl engaging it, and further with at least one locking lever, preferably a central locking lever, and with at least one (electric) motor drive. In addition at least one actuating lever for operation from inside and/or outside can be provided.
A motor-vehicle door latch of the above-described type is for example known through German published application 196 27 246. Here a device for fast unlocking of the door latch is also described. Preferably it is constituted by a solenoid which moves between an extra-security (antitheft-on) position and an unlocked position. In the unlocked position the latching pawl and the release lever coact such that on actuation of the (outside) actuating lever the pawl is lifted off the pivotal bolt and the respective motor-vehicle door can be opened.
The above-described motor-vehicle door latch has proven effective in practice, but requires on the one hand the described and specially manufactured solenoid and on the other hand a separate and independent central-locking drive. This is expensive.
In addition for some time motor-vehicles are known to have so-called keyless entry systems that allow entry into the vehicle without the use of the otherwise standard mechanical key. A keyless entry system functions in that the vehicle user carries an identifying device (e.g. a code card) and on approaching the vehicle or when the outside actuator (door handle) is actuated, a transmitter/receiver system exchanges data between the identifying device and an on-board controller to determine (by comparing codes) if entry is authorized. If the necessary authorization is established, the electronic controller transmits signals to at least one of the door latches of the motor vehicle that is opened by an automatic motorized control element. Such a motor-vehicle door latch is for example described in German 3,820,248.
In case a door latch in motor vehicles is for example equipped with a keyless entry system, it is particularly necessary when additional use is made of an antitheft mechanism to reduce the time between triggering of the opening procedures and actual unlocking of the door (preferably less than 40 ms) such that the system is convenient to operate. This is significant because the motor-vehicle door latch must after receiving the door-unlock signal first move from the antitheft-on (extra-security) position and into the unlocked position. Here the central locking drive normally has an eccentric control pin and at least one fork seat and must execute two revolutions, so that there is a certain delay (see in this regard German 196 32 781). The invention proposes a solution to this problem.
It is a technical object of the invention to improve on a motor-vehicle door latch of the above-described type such that a relatively delay-free opening of the motor-vehicle door takes place with no particular extra construction cost.
This object is achieved by the invention in a motor-vehicle door latch of the described type wherein for fast unlocking a blocking lever is provided engaging the locking lever, preferably in its locked and/or antitheft-on position, the locking lever being separated from the locking lever by means of the (electric) motor drive during fast unlocking so that the locking lever can be moved into its unlocked position. This can be effected actively or passively. In the first case the blocking lever after fast unlocking is clear and can be shifted by its own setting member into the necessary unlocked position. Normally this is done in that the locking lever is moved during the fast unlocking automatically, preferably by a spring, into the unlocked position.
Also in the scope of the invention is a fast unlocking of the described motor-vehicle door latch. Fast unlocking means that the motor-vehicle door latch in general is moved directly from the antitheft-on, extra-security position or the locked position into the unlocked position. Thereafter the respective motor-vehicle door can be opened by operation of the actuating lever (or otherwise). Thus it is conceivable that the described actuating lever is actuated by an outside door handle so that the latch pawl is lifted off the pivotal bolt and then the door can be opened. Basically the fast unlocking can thus be followed by a conventional operation of the actual latch.
A motor-vehicle door latch can be any latch that serves not only for side doors but also for the trunk lid, tailgate, or hood, and even for the gas cap or the like. In addition it is without doubt within the scope of the invention to provide such a motor-vehicle door latch with additional devices for electrical opening, antitheft action, and infant security. Electrical opening in this case means that the latch pawl is moved out of engagement or latching connection with the pivotal bolt by means of an (electric) motor force.
In addition motor-vehicle door latches are included where access is mechanical, by means of a door key, door lock, and the respective door-lock nut or even by an electronic key (keyless entry). Of course in the last case the above-described data exchange takes place automatically or is triggered by the user via an actuatable remote controller (with its own transmitter).
According to a first alternative of the invention in order to have locked and antitheft functions or locked and antitheft positions, the locking lever has two seats. These seats are engageable with a nose on the blocking lever, as described in German patent application 199 34 128.1. In this regard more details are seen in the discussion of the drawing.
The two seats can be formed as part-circular pockets with different radial spacings from a rotation axis of the locking lever so that different positions of the blocking lever are achieved in the locked and antitheft positions. This is normally necessary to ensure that the actuating lever, for example in the locked position of the blocking lever, can lift out of the seat. On the other hand such a system is not usable in the antitheft-on position of the motor-vehicle door latch and is also not desired. In this position the actuating lever moves freely.
According to another alternative embodiment of the invention the locking lever has a pin working with the blocking lever. This pin engages in a pin seat on the blocking lever. In order to establish an antitheft-on position, in addition there is a (motor-actuated) antitheft lever. This antitheft lever can be moved during fast unlocking by means of the blocking lever from the antitheft-on to the antitheft-off position. Simultaneously the pin seat on the blocking lever is lifted off the pin on the locking lever so that this pin and its locking lever are freed. In this manner the already described motor drive serves to operate the blocking lever.
The blocking lever can cooperate with a spring-loaded force-transmitting lever that when operated by the motor drive entrains the locking lever for fast unlocking. This is most simply done in that the force-transmitting lever and the blocking lever are mounted on a common pivot axis and are usually at least partially overlapping and that the force-transmitting lever has for the necessary coupling an edge engaging the blocking lever during fast unlocking. In the opposite actuation direction (of the (electric) motor drive) the force-transmitting lever is deflected by this drive. This is necessary in order that the drive can according to the invention have an additional function, namely not only fast unlocking but also central locking.
According to a further alternative embodiment, the blocking lever has an elongated slot at which it is slidably pivoted and along which it is spring-biased. The (electric) motor drive for fast unlocking engages against an actuating edge of the blocking lever. The blocking lever is deflected via the slidable pivoting on opposite actuation movement of the (electric) motor drive (like what was described above) by movement along the slot.
In order to combine the various functions according to the invention, it is further suggested that the (electric) motor drive be used both for central locking (as well as if necessary for fast unlocking) and to this end has an electric motor with an output wheel or disk and an eccentric control bump. This control bump engages in at least one fork seat on the locking lever for (central) locking. Preferably two fork seats are provided, one for the locked position and one for the antitheft-on position (so long as no additional antitheft lever is employed).
Due to the double-duty of the (electric) motor drive the control bump also coacts not only with the force-transmitting lever and/or with the abutment edge of the blocking lever but additionally, as described, with the one or two fork seats on the locking lever.
As a result an extremely compact construction of the described motor-vehicle door latch is obtained that is particularly good for fast unlocking. In fact the output wheel engages with its control bump normally already after about a quarter turn with the blocking lever or its force-transmitting lever so that unwanted delay is excluded on fast opening of the motor-vehicle door latch. This is also the case when it has to be unlocked when in the antitheft-on position and when the unlocking signal is issued by the (central) locking system. In both cases one gets a nearly delay-free unlocking so that the attached motor-vehicle door can be opened immediately.
At the same time the (electric) motor drive takes over the function of moving the locking lever, in particular a central locking lever, into its locking position and/or antitheft-on position. As a result a further drive is not necessary, for a considerable cost advantage. Other features of the invention have a similar effect of setting the optional antitheft lever by means of a single (electric) motor drive. In spite of this basic possible one can also of course use an additional second drive.
The invention always has a particularly simple and clear construction. Here the principal advantages of the invention can be seen.
In the following the invention is described more closely with reference to a single embodiment. Therein:
FIG. 1 is the latch mechanism belonging to the motor-vehicle door latch according to the invention which is shown at a right angle to the elements shown in the following figures;
FIG. 2 is the motor-vehicle door latch according to the invention in a first embodiment in the locked position;
FIG. 3 is the motor-vehicle door latch according to FIG. 2 in the antitheft-on position;
FIG. 4 is another embodiment of the motor-vehicle door latch according to FIGS. 2 and 3;
FIG. 5 is a further variant of the motor-vehicle door latch with antitheft lever in the antitheft-on position; and
FIG. 6 is the motor-vehicle door latch according to FIG. 5 in the antitheft-off position.